Sen. Pat Toomey (R-Pa.) says Alabama Republican Senate candidate Roy Moore, who has been accused of sexual misconduct with teenage girls, should withdraw from the race.

“You know, this is a terrible situation,” Toomey said Sunday on NBC’s “Meet the Press.” “Nearly 40-year-old allegation. We’ll probably never know for sure exactly what happens. But from my point of view, you know, I have to say, I think the accusations have more credibility than the denial. I think it would be best if Roy would just step aside.”

In an explosive report published Thursday by The Washington Post, four women alleged that Moore pursued them when they were teenagers and he was in his early 30s. The most serious story came from a woman who said she was just 14 when Moore sexually assaulted her.

Moore has denied the charge made against him by the 14-year-old. But when asked Thursday whether he remembered dating women in their teens when he was in his 30s, Moore told Fox News’ Sean Hannity: “Not generally, no.”

Toomey, while saying he didn’t find Moore’s denials “terrible credible,” also questioned the timing of the allegations.

“When someone waits 40 years before they make an accusation, you know, that raises a question itself,” he said. “So it’s probably not knowable. But there seems to be enough there that it’s very disturbing.”

Toomey suggested the party explore a write-in campaign with another GOP candidate.

“I think [appointed Alabama Sen.] Luther Strange would be a strong candidate for a write-in. But a write-in is very difficult, let’s face it. So there’s no easy solution to this. I think we should consider a write-in.”

Strange was appointed early this year to the seat Republican Jeff Sessions gave up to become President Donald Trump’s attorney general. Moore defeated Strange in a late September primary runoff for the GOP nomination in the Dec. 12 special election for the seat.

Three GOP senators have withdrawn their endorsements of Moore following the Post story: Bill Cassidy (La.), Steve Daines (Mont.) and Mike Lee (Utah). Sen. Bob Corker (R-Tenn.), who recently announced he would not be seeking re-election next year, called Moore’s nomination “a bridge too far” even before the allegations of sexual misconduct surfaced.

Moore is a far-right social conservative who vocally condemns homosexuality. He twice removed from the Alabama Supreme Court for defying federal court orders.

Two senior members of Trump’s administration expressed concernduring interviews on Sunday the allegations leveled against Moore, but stopped short of calling on him to end his candidacy.

Treasury Secretary Steven Mnuchin told CNN that Moore should step down “if the allegations prove to be true.” But he did not detail what proof against Moore would be sufficient ― a stance similar to the one taken by White House press secretary Sarah Huckabee Sanders and Senate Majority Leader Mitch McConnell (R-Ky.) when the Post story first broke.

A former prosecutor who worked with Moore in the early 1980s told CNN on Saturday that it was “common knowledge” that Moore dated teenagers — and Moore’s colleagues thought it was “weird.”

White House director of legislative affairs Marc Short said on “Meet the Press” that sexual misconduct allegations like those leveled against Moore “should disqualify anyone from serving in public office.” He added that no Senate seat is “more important than the issue of child pedophilia,” and that there is “a special place in hell for people who have done those crimes.”

But he cautioned “we here in Washington have to be careful as well in this,” given that Moore has denied the charge involving the 14-year-old.